The process for the production of nitric oxide is known as the Ostwald process and has essentially remained unchanged, since its inception in the first decades of the twentieth century. Ostwald's patent was dated 1902 and when combined with Haber's development of synthesising ammonia directly from nitrogen, in 1908, the basis for the commercial production of nitric acid, which is used today, was in place.
The basis of the current Ostwald's process is combustion of ammonia over a platinum based metal or alloy catalyst in the form of a gauze or mesh or net. The gauzes are either woven or knitted.
Over the last sixty years, many attempts have been made to replace the expensive platinum-based combustion catalyst with a lower cost catalyst. To date, the only commercially available oxide-based catalyst for ammonia combustion is produced by Incitec Pivot Ltd (Australia). This is based on a cobalt oxide phase. However, in terms of its selectivity of combustion of ammonia to the desired nitric oxide product, its performance is inferior to that of platinum-based systems. The cobalt oxide based systems have shown selectivity levels of about 90% in commercial units, compared to the 94 to 98% achieved with platinum-base catalysts.